/*
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 */

package homework;

/**
 *
 * @author Administrator
 */
public class ID {
    public static void main(String[] args) {
        String ID="45021119911127051";
        boolean flag=true;
        if(ID.length()!=18){
            flag=false;
        }
        if(!(ID.startsWith("450"))){
            flag=false;
  }
        if(flag)
        {
            System.out.println("ID是合法的");
    }
        else{
            System.out.println("ID是不合法的");
        }

}
}